A few questions regarding parts. There are differences in part values between your build and the one in the On Semi spec. sheet. R1 and R2, I'm assuming, are replaced by the pot. But there is a 1500pF cap on the spec sheet that you don't mention, along with a 0.22 ohm resistor and a 330uF cap. Could you post a copy of your final schematic? I'd like to avoid creating a cockroach-sized roadside bomb :)

Also, what did you do for the 170uH coil? There are 150uH and 20uH coils available cheap that I'll probably use in series before winding my own.

Best if you have a meter with a real mains switch, for meters with Buttons like on your remote the Voltage must be allways there. This converter consumes 3mA in Standby, if you use it often not a problem otherwise it may have killed the accu by deep discharge when you need it. Better to put the protection circuit of an cell phone accu in additionally, if there is place left.

The IC is specified for input voltages between 3-40V and seems to crap out not far below the 3V mark, so probably adding a general purpose diode in series on the input will serve as a simple undervoltage lockout ;-)

I was to lazy to doe that and simply put two in series. Bur then it is of course dangerous when you measur higher than 50 V. Because they are connected to the accu, which will not fit inside the Meter.